Today, after weeks of stalemate in Congress, President Bush will sign the Aviation and Transportation Security Act. On the key sticking point, federalization of passenger screeners, the Senate largely got its way: Some 28,000 screeners will now become federal employees, the largest single expansion of the federal workforce in decades.

No one disputed the need for changes in the system; anyone who has had his or her bags checked by a sleepy-eyed screener knows major improvement is needed. Both sides supported critical changes in qualifications, training, pay and oversight.

But will turning screeners into federal employees itself improve their performance?

It's a curious argument, and one that defies common experience. Think of the last time you went to the Department of Motor Vehicles.

It's a model even the Europeans have rejected. In country after country, screening functions have been shifted to the private sector, even in big-government strongholds such as Germany and France. A key reason for this is accountability: the ability to dump non-performing workers without delay or ceremony.

Anyone who has worked in government knows that's virtually impossible to do there. (While the bill formally exempts screeners from normal job protections, many in Congress are skeptical, seeing room for legal challenge or political interference.)

The legislation maintains a sliver of hope for alternatives.

Private contractors, certified and supervised by the federal government, will be allowed at up to five airports after a year, and more after 3 years. It's a cumbersome process: Airports must make an explicit request; the transportation secretary can't use his own discretion to make changes. Nevertheless, this alternative may prove to be important should the federalized system fail to achieve needed improvements, or as many fear, make things worse.

Despite the controversy, screening is only one part of the legislation. The document addresses a host of other security issues, many of which have much more to do with Sept. 11. These range from cockpit doors to always-on transponders.

It even acknowledges the government's own Sept. 11 failures, calling for more sharing of terrorist information by federal agencies.

No one doubts there is more to be done. In the search for solutions, however, policymakers should see the resources and abilities of the private sector as a needed ally, not an enemy.

James Gattuso is vice president for policy at the Competitive Enterprise Institute.